Feel free to cook sliced chicken sausage separately, then add to the bowls of the meat lovers for a healthier lasagna bite.
Heat the olive oil in a non-stick skillet over medium heat. Add the onion, garlic, and brown mushrooms, and cook until the begin to soften, about 4-5 minutes.
Add the onion mixture to the insert of a 6 quart slow cooker with the zucchini, crushed tomatoes, tomato sauce, vegetable broth, bay leaves, basil, oregano, red pepper flakes, kosher salt and black pepper. Set the slow cooker on low and cook for 7 hours or on high and cook for 3 1/2 to 4 hours.
Once the cooking time is done, cook the lasagna noodles according to the package directions, drain, and add to the soup. Cut them into smaller pieces if you'd like. Add the spinach and warm until wilted. Mix in half of the ricotta cheese mixture. Ladle into soup bowls and top with a dollop of the remaining ricotta cheese topping and sprinkle with more parsley and basil.